This fairy-tale castle would make Dracula (who is said to have been imprisoned there) jealous.

A perfectly circular lake is formed by the crater of an ancient underwater volcano.

Classical ruins that remember ancient Rome's presence in Africa.

Despite a fraught and controversial history this African island holds a powerful monument to the tragedy of the slave trade.

This fortified sand barrier dividing a contested territory is the longest minefield in the world.

Light still pours into the ruins of this ancient Islamic observatory.

A shrine of fire worship built on top of a natural flame.

This Soviet-era "closed town" was a top secret uranium producer often left off of maps.

Man-made mineral caves house massive bat colony.

The labyrinthine home of the National Archives of Estonia is an experimental blend of architecture, art, and history.